Re: Shake some supercooled water and you get ice, why?

nuny@xxxxxxxx wrote:
On Feb 18, 4:01 pm, andy everett <vze2q...@xxxxxxxxxxx> wrote:


I set out 5 half litter bottles of spring water after lunch. Temps just
below freezing. Around 6 pm, temps now in the low 20's, I put a chunk of
ice into one of the bottles, being careful opening the cap. Ice
instantly formed around the piece of ice. We know now the water in the
bottles are in a super cooled state. Next grab a bottle and shake
vigorously in such a way to impart circular motion. Small crystals seen.
Allow things to cool further. Open cap carefully and drop in a very
small amount of snow. Starting from the top a pretty group of ice
crystals forms.

On the last bottle I shook vigorously, the bottle became cloudy with
crystals, quickly I poured the mixture of water and crystals into a
measuring cup and filtered the crystals out with a paper towel. The
paper towel was squeezed to get more of the water out. Out of 16.9 oz.
of water less then .9 oz of the water was ice.


Excellent!


Time to get a good thermometer.


Yes, absolutely. I'd just love to know the temp of the remaining
water, and the temp of the supercooled water pre-freezing.

BTW, can you photograph the ice crystals per the drop-in-the-snow
trick?

I think I would need a better camera then I have. The human eye is pretty good at seeing detail up close. Will try.

How far down into the water did they extend?

After only a minute the ice that formed, all in the form of very thin sheets with beautiful detail that only nature can "paint", extended to the bottom.

Also, how'd the
rate of growth of the crystals go, fast, then slow, or what?

On a human scale slow, time scale in seconds, You-tube has many great videos that show the effect. If the bottles are too cold I think you would miss more subtle changes.



I set out another 5 bottles around 7 pm. In the low 20's and down to 11F this morning. I also put one bottle of spring water into a clean glass and covered with plastic. Shoulder hurts, can't sleep, 3:15 am. Of the 5 bottles only 2 showed no signs of ice (one kicked over). I grabbed one of the clear bottles and shook it violently, it iced up instantly. With the last remaining unfrozen bottle I was more subtle. I tapped the side with a flick of a finger, nothing. Then with a gentle back and forth motion, rotation about the bottom of the bottle, in a matter of 3 seconds the water clouded up, starting at the top and working its way down completely clouding the bottle.

The water in the glass froze. The glass looked clean.


The article that Ed refereed to suggested that above some temperature but below freezing the supercooled water (in glass I think) would not freeze with aggressive shaking. Maybe it is the plastic container that is different.



Mark L. Fergerson

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